Short answer: the Partybox Ultimate if you want the deepest bass available and always have it near an outlet; the Bromley 750 if you need it to actually run on battery. These rank #13 and #3 out of 13 large-party speakers, at $999.99 and $1,899.95, with the Partybox Ultimate costing $899.96 more.
The Partybox Ultimate has no battery at all - it’s mains-power only. That’s the real dividing line between these two, more than sound quality: the Bromley 750 runs 40-plus hours cordless, while the Ultimate has to stay plugged in. In exchange, the Ultimate is rated at 1100W against the Bromley 750’s 400W, and our own notes call it the absolute deepest bass of any Bluetooth speaker we’ve covered - a category the Bromley 750 doesn’t compete in, given its own notes flag its bass as not particularly deep and its frequency response as unremarkable.
Both are wheeled and heavy - the Ultimate is the bigger of the two at 39 kg (86 lbs) against the Bromley 750’s 23.9 kg (52.7 lbs) - and both take guitar and karaoke-style microphone input, with the Bromley 750 adding true XLR-level jacks the Ultimate doesn’t have.
Buy the Partybox Ultimate if raw bass depth is the priority and portability isn’t. Buy the Bromley 750 if you actually need it to run away from an outlet.
Want more options? Browse the full Portable Bluetooth rankings.
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Specifications Side By Side
| Marshall Bromley 750 | JBL Partybox Ultimate | |
|---|---|---|
| Price | $999.99 | $1,899.95 |
| Ranked | #13 of 13 in Large Party Size Portable Bluetooth Speakers | #3 of 13 in Large Party Size Portable Bluetooth Speakers |
| Aux Input | Yes (3.5mm, RCA) | Yes |
| Battery Life | 40+ hours (Manufacturer specified) | No Battery |
| Bluetooth | Yes | Yes |
| Bluetooth Codecs | SBC, AAC, LC3 | SBC |
| Guitar Input | Yes | Yes |
| IP Rating | IP54 | IPX4 |
| Microphone Input | Yes (2x XLR/6.35mm combo) | Yes (Karaoke mode with echo effect) |
| Power Bank | Yes (USB-C) | Yes (USB-A, 5V/2.1A) |
| Power Input | USB-C | AC Power cord |
| Weight | 52.7 lbs (23.9 kg) | 86 lbs (39 kg) |
| XLR Input | Yes (2x combo) | - |
| App | Yes (Marshall Bluetooth app) | Yes |
| Built-in Microphone | No | No |
| EQ | Yes | Yes (3 band) |
| Party Mode | Yes (Auracast) | Yes (Auracast) |
| Stereo | Yes | Yes |
| Omnidirectional | Yes | No |
| TWS | No | Yes |
| USB Playback | No | Yes |
| Wi-Fi | No | Yes |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 16.3” x 25.7” x 14” (413 x 652 x 355 mm) | 17.9” x 41.3” x 17.3” (455 x 1049 x 440 mm) |
| Drivers | 2x 10” woofers, 2x 5.25” mid-ranges, 2x 1” tweeters, 2x 0.8” tweeters | 2x 9” subwoofer, 2x 4.5” midrange, 2x 2.75” tweeter |
| Amplifier Power | 400W | 1100W |
| Digital Aux Input | Yes (USB-C) | No |
| Removable Battery | Yes | - |
| Charging Time | 3.5 hours | - |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | - |
| Lights | Yes | Yes |
| Strap | No | No |
| Wheels | - | Yes |
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